Recently, research on a safety driving service (cooperative collision avoidance, forward collision warning, lane change, and the like) using an inter-vehicular communication technology, such as IEEE 802.11P has been actively conducted. The purpose of the vehicle safety driving service is to provide a driver with a safer and more pleasant driving environment by inducing safe driving of a vehicle and improving a traffic congestion situation by monitoring a driving situation in real time through inter-vehicular short-range wireless communication.
The vehicle safety driving service generally has a function of periodically broadcasting a vehicle safety message to neighboring vehicles. The vehicle safety message basically includes a vehicle location vector and a time stamp, such as a location, a speed, and a movement direction of a vehicle. This enables each vehicle to recognize current driving situations of neighboring vehicles in real time, and rapidly responds to a dangerous situation, thereby helping to prevent an accident.
Accordingly, one of the significant factors for determining reliability of the safety driving service is reliable transception of a safety message. However, in a traffic congestion region in which there is a lot of vehicles, a channel load of a wireless network is rapidly increased due to transmission of the safety message without control, so that a network congestion phenomenon, such as an unlimited increase in a channel access delay or a sharp increase in a packet loss, is generated. The phenomenon may cause a fatal defect to the safety driving service close to a life of a driver.